Method for making semiconductor devices having gradual slope contacts

ABSTRACT

The present invention is directed to a method for forming semiconductor devices and semiconductor device precursors having gradual slope contacts. The method for forming a semiconductor precursor includes the steps of: forming a layer of conductive material in a first layer; forming a layer of a hard mask material onto at least a portion of the first layer; etching the layer of hard mask material to expose a portion of the first layer; forming facets on the layer of hard mask material; and forming a via in the first layer such that the via extends through the first layer to expose at least a portion of the layer of conductive material.

FIELD OF THE INVENTION

[0001] The present invention relates, in general, to contact etchprocesses and, more particularly, to sloped contact etch processes.

BACKGROUND OF THE INVENTION

[0002] Dynamic random access memory (DRAM) semiconductor devices andstatic random access memory (SRAM) semiconductor devices typicallyinclude an insulating layer of a dielectric material to electricallyseparate one conductive layer from another. Often, the two conductivelayers are connected by means of a hole, commonly known as a “contact”or “via,” in the insulating layer. Sometimes the via must have a slopedor faceted profile to provide proper step coverage of appropriatethickness of the conductive layer. Vertical contact profiles oftenresult in unacceptable step coverage and excessively sloped profilesprovide good step coverage but result in highly enlarged vias. Enlargedvias may cause electrical shorting between or within conductive layersand may also reduce the density of the circuit features by limiting theproximity of the devices. Thus, providing an adequate contact slope iscritical to achieving acceptable contact step coverage.

[0003] U.S. Pat. No. 5,320,981 to Blalock describes a process forforming a sloped via. In this process, a photoresist mask is used todefine an etch area on a dielectric layer. The dielectric layer isetched either isotropically or anisotropically to expose an underlyingconductive layer. After the dielectric layer has been etched, thephotoresist mask is removed and a second etch is performed. This secondetch is a plasma etch and is conducted with a material, such as argon,krypton or xenon, so that as close as possible to a purely physical, asopposed to chemical, erosion takes place. The second etch forms a facetin the side walls of the via and redeposits the eroded dielectricmaterial onto the opposite side wall.

[0004] However, when a photoresist material is used during etching of avia, particles of the photoresist material become deposited in theresulting via and on the conductive material. These particles ofphotoresist material affect the subsequent step coverage and theresulting conductivity of the semiconductor device. Further, plasmaetching of a material is not a selective process and in the case offacet etching, portions of the semiconductor device other than theportion being facet etched may be damaged. Thus, a need still exists inthe art for a process for forming a semiconductor devices having agradual slope contact.

SUMMARY OF THE INVENTION

[0005] The present invention meets the current needs in the art byproviding a method for forming semiconductor devices having gradualslope contacts. The present invention also provides a variety ofsemiconductor devices having gradual slope contacts.

[0006] One aspect of the present invention is directed to a method formaking a semiconductor device precursor. The method comprises the stepsof: forming a layer of conductive material in a first layer; forming alayer of a hard mask material onto at least a portion of the firstlayer; etching the layer of hard mask material to expose a portion ofthe first layer; forming facets on the layer of hard mask material; andforming a via in the first layer such that the via extends through thefirst layer to expose at least a portion of the layer of conductivematerial.

[0007] Another aspect of the present invention is directed to a methodfor forming a semiconductor device precursor. The method comprises thesteps of: forming a layer of conductive material in a first layer;forming a layer of a hard mask material onto at least a portion of thefirst layer; forming a layer of etch resistant material on the layer ofhard mask material; patterning the layer of etch resistant material;etching the layer of hard mask material to expose at least a portion ofthe first layer; forming facets on the layer of hard mask material; andforming a via in the first layer such that the via extends through thefirst layer to expose at least a portion of the layer of conductivematerial.

[0008] Still another aspect of the present invention is directed to amethod for forming a semiconductor device precursor. The methodcomprises the steps of: forming a layer of conductive material in afirst layer; forming a layer of a hard mask material onto at least aportion of the first layer; forming a layer of etch resistant materialon the hard mask material; patterning the layer of etch resistantmaterial; etching the layer of hard mask material to expose at least aportion of the first layer and to form opposing sidewalls in at least aportion of the first layer; bombarding the hard mask material with anion source to form facets; depositing a portion of the material removedfrom the layer of hard mask material on opposite sidewalls of the firstlayer; forming a via in the first layer such that the via extendsthrough the first layer to expose at least a portion of the layer ofconductive material.

[0009] Yet another aspect of the present invention is directed to amethod for forming a semiconductor device. The method comprises thesteps of: forming a layer of conductive material in a first layer;forming a layer of a hard mask material onto at least a portion of thefirst layer; etching the layer of hard mask material to expose at leasta portion of the first layer and to provide the hard mask material withfacets; forming a via in the first layer such that the via extendsthrough the first layer to expose at least a portion of the layer ofconductive material; and forming a metal interconnect in the via, themetal interconnect contacting at least a portion of the layer ofconductive material.

[0010] A further aspect of the present invention is directed to asemiconductor device precursor having a gradual slope contact formed bythe method comprising the steps of: forming a layer of conductivematerial in a first layer; forming a layer of a hard mask material ontoat least a portion of the first layer; etching the layer of hard maskmaterial to expose a portion of the first layer; forming gradual slopecontact on the layer of hard mask material; and forming a via in thefirst layer, the via extending through the first layer to expose atleast a portion of the layer of conductive material.

[0011] Another aspect of the present invention is directed to asemiconductor device precursor having a gradual slope contact formed bythe method comprising the steps of: forming a layer of conductivematerial in a first layer; forming a layer of a hard mask material ontoat least a portion of the first layer; forming a layer of etch resistantmaterial on the layer of hard mask material; patterning the layer ofetch resistant material; etching the layer of hard mask material toexpose at least a portion of the first layer; forming gradual slopecontact on the layer of hard mask material; and forming a via in thefirst layer, the via extending through the first layer to expose atleast a portion of the layer of conductive material.

[0012] Still another aspect of the present invention is directed to asemiconductor device precursor having a gradual slope contact formed bythe method comprising the steps of: forming a layer of conductivematerial in a first layer; forming a layer of a hard mask material ontoat least a portion of the first layer; forming a layer of etch resistantmaterial on the hard mask material; patterning the layer of etchresistant material; etching the layer of hard mask material to expose atleast a portion of the first layer and to form opposing sidewalls in atleast a portion of the first layer; bombarding the hard mask materialwith an ion source to form a gradual slope contact; depositing a portionof the material removed from the layer of hard mask material on oppositesidewalls of the first layer; forming a via in the first layer, the viaextending through the first layer to expose at least a portion of thelayer of conductive material.

[0013] Yet another aspect of the present invention is directed to asemiconductor device having a gradual slope contact formed by the methodcomprising the steps of: forming a layer of conductive material in afirst layer; forming a layer of a hard mask material onto at least aportion of the first layer; etching the layer of hard mask material toprovide the hard mask material with a gradual slope contact; forming avia in the first layer, the via extending through the first layer toexpose at least a portion of the layer of conductive material; andforming a metal interconnect in the via, the metal interconnectcontacting at least a portion of the layer of conductive material.

[0014] A further aspect of the present invention is directed to a methodfor making a semiconductor device having a gradual slope contactcomprising the steps of: forming a layer of dielectric material on asubstrate, wherein the dielectric material is selected from the groupconsisting of silicon oxide, silicon nitride and polyimide film andwherein the substrate is selected from the group consisting of aluminum,copper and polycrystalline silicon; forming a layer of conductivematerial within the layer of dielectric material, the layer ofconductive material being surrounded by the layer of dielectricmaterial; depositing a layer of hard mask material on the layer ofdielectric material, the hard mask material being selected from thegroup consisting of tungsten, tungsten silicide, polycrystallinesilicon, titanium, titanium nitride, titanium silicide andtitanium-tungsten alloys; forming a photoresist layer on the layer ofhard mask material; exposing the photoresist layer to form a pattern onthe photoresist layer; etching the layer of hard mask material accordingto the pattern on the photoresist layer to expose the layer ofdielectric material and to form sidewalls in the exposed portion of thelayer of dielectric material; removing the photoresist layer;anisotropically etching the layer of hard mask with an inert material toform gradual slope contact on the layer of hard mask material;depositing the hard mask material removed by the anisotropic etchingonto the sidewalls of the exposed layer of dielectric material to form agradual slope contact; etching the dielectric material to expose aportion the conductive layer; and forming a metal interconnect with theexposed portion of the conductive layer, wherein the metal which formsthe metal interconnect is selected from the group consisting ofaluminum, copper, gold, aluminum-titanium alloys and aluminum-copperalloys.

[0015] A further aspect of the present invention is directed to asemiconductor device precursor. The semiconductor device precursorincludes a substrate. A layer of dielectric material is formed on atleast a portion of the substrate. A layer of conductive material isformed within the layer of dielectric material so that the layer ofconductive material contacts at least a portion of the substrate. Alayer of hard mask material is formed on at least a portion of the layerof dielectric material. The layer of hard mask material has a pair offacets formed therein by anisotropic etching. The facets and the layerof dielectric material define a via which exposes at least a portion ofthe layer of conductive material.

[0016] A still further aspect of the present invention is directed to asemiconductor device. The semiconductor device includes a substrate. Alayer of dielectric material is formed on at least a portion of thesubstrate. A layer of conductive material is formed within the layer ofdielectric material such that the layer of conductive material contactsat least a portion of the substrate. A layer of hard mask material isformed on at least a portion of the layer of dielectric material. Thelayer of hard mask material has facets formed therein by anisotropicetching. The facets and the layer of dielectric material define a viawhich exposes at least a portion of the layer of conductive material.Finally, an interconnect material is formed in the via.

[0017] Accordingly, it is an object of the present invention to providea method for forming a semiconductor having a gradual slope contactwhich increases the step coverage and resulting conductivity of thesemiconductor device. Other objects and advantages of the invention willbe apparent from the following detailed description, the accompanyingdrawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 presents a cross sectional view of a semiconductor deviceof the present invention.

[0019]FIG. 2 presents a cross sectional view depicting the formation ofa semiconductor device formed by the method of the present invention.

[0020]FIG. 3 presents a cross sectional view depicting the formation ofa semiconductor device formed by the method of the present invention.

[0021]FIG. 4 presents a cross sectional view depicting the formation ofa semiconductor device formed by the method of the present invention.

[0022]FIG. 5 presents a schematic diagram of the angle of ionimpingement on a material used in the manufacture of semiconductordevices and the consequent shape of the structures upon removal.

[0023]FIG. 6 presents a cross sectional view of a semiconductor deviceprecursor formed by the method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0024] For the purposes of the present application, the preposition “on”refers to formation in contact with the surface of a particular layer,while “over” refers to a formation above or in contact with a surface ofa particular layer.

[0025] A semiconductor device 10 formed according to the process of thisinvention is shown in FIG. 1. The device 10 includes a substrate 12 onwhich a layer 14 is formed. A layer 18 of conductive material 20 ispositioned over the substrate 12. The layer 18 of conductive material 20is formed in the layer 14 and is desirably surrounded by the layer 14.The layer 18 of conductive material 20 may also be positioned on thesubstrate 12. A layer 22 of a hard mask material 24 is formed on thelayer 14. The layer 14 has a pair of side walls 26 formed therein. Thelayer 22 of hard mask material 24 has a planar surface 28 and has facets30 formed therein. The side walls 26 in the layer 14 and the facets 30in the layer 22 of hard mask material 24, together, define a via 32. Ametal interconnect 34, which contacts at least a portion of the layer 18of conductive material 20, is formed in the via 32. The facets 30 formgradual slope contacts 46 with the metal interconnect 34. The layer 14also has a pair of shoulders 36 formed therein. The shoulders 36 arecovered with a deposit 38 of hard mask material 24.

[0026] The substrate 12 is formed from any material currently in use inthe art which is used to form substrates for semiconductor devices suchas semiconductor device 10. Useful materials include, but are notlimited to, doped or undoped silicon, doped or undoped polycrystallinesilicon, gallium arsenide, gallium phosphide and indium phosphide.

[0027] The layer 14 is desirably an insulating material 16 which can beany material currently in use in the art as an insulator or adielectric. Useful insulating materials 16 include, but are not limitedto, tetraethyl orthosilicate (TEOS), nitrides, oxides and polyimides.

[0028] The conductive material 20 is any material which conducts anelectric current. Useful materials include, but are not limited to,polycrystalline silicon, aluminum, copper, aluminum-copper alloys,aluminum-titanium alloys and gold. Desirably, the conductive material 20is an aluminum-copper alloy.

[0029] The hard mask material 24 is formed from any material which doesnot produce polymeric residues during an etching process and which isnot removed by solvents used to remove photoresist materials from thesurface of semiconductor precursor or device. Materials useful forforming the layer 22 of hard mask material 24 include, but are notlimited to, tungsten, tungsten silicide, polycrystalline silicon,silicon nitride, titanium, titanium nitride, titanium silicide, andtitanium-tungsten alloys.

[0030] The metal interconnect 34 is formed from any material currentlyin use in the art which conducts an electric current. Useful materialsinclude, but are not limited to, polycrystalline silicon, aluminum,copper, aluminum-copper alloys, aluminum-titanium alloys and gold.Desirably, the conductive metal interconnect 28 is formed from analuminum-copper alloy.

[0031] The semiconductor device 10 is formed by the following process.As shown in FIG. 2, the layer 14 is formed on at least a portion of thesubstrate 12 by any conventional deposition or forming process. Next,the layer 18 of conductive material 20 is formed in the layer 14 and ispositioned over or on the substrate 12. The layer 18 of conductivematerial 20 is formed so that it is surrounded by the layer 14 at leaston three sides, or is surrounded on all sides if the layer 18 ofconductive material 20 does not contact the substrate 12. For example,the layer 18 of conductive material 20 can be formed in the followingmanner. After the layer 14 has been formed on the substrate 12, a layerof a photoresist material is formed on the layer 14. The photoresistlayer is then patterned and etched by conventional processes to form anarea in which the layer 18 of conductive material 20 can be formed. Thelayer 18 of conductive material 20 is then formed in the area. After thelayer 18 of conductive material 20 has been formed in the area, thelayer 14 is formed over the layer 18 of conductive material 20 tosurround the layer 18 of conductive material 20.

[0032] After the layer 18 of conductive material 20 has been formed inthe layer 14, the layer 22 of the hard mask material 24 is deposited onat least a portion of the layer 14. The layer 22 of hard mask material24 is deposited by any conventional means used to deposit a metallicmaterial onto a substance. Useful methods include chemical vapordeposition, evaporation and sputtering. Desirably, the layer 22 of hardmask material 24 is deposited by chemical vapor deposition. The layer 22of hard mask material 24 can have any thickness and desirably has athickness from about 500 Å to about 1000 Å.

[0033] With reference to FIG. 3, once the layer 22 of hard mask material24 has been deposited on the layer 14, a layer 40 of an etch resistantmaterial 42 is formed on at least a portion of the layer 22 of hard maskmaterial 24. The etch resistant material 42 is any conventional materialused in semiconductor etching processes. Desirably, it is a photoresistmaterial. After the layer 40 of etch resistant material 42 has beenformed on the layer 22 of hard mask material 24, the layer 40 of etchresistant material 42 is patterned or exposed in a conventional manner.The layer 22 of hard mask material 24 is then etched according to thepattern. The layer 22 can be etched either isotropically oranisotropically. An isotropic etch can be performed using hydrofluoricacid or any other acid currently used in the art to wet etchsemiconductor substrates. Desirably, the layer 22 is anisotropicallyetched using a gas plasma etch, an ion beam etch, or a reactive ion etchto avoid the formation of a retrograde profile which often results fromthe use of isotropic etching processes. More desirably, the layer 22 ofhard mask material is plasma etched.

[0034] The etch is performed so that the layer 22 of hard mask material24 is etched through its entire thickness to expose at least a portionof the layer 14. As shown in FIG. 3, a slight over etching desirablytakes place and results in a portion of the layer 14 also being etched.This over etching is desirable to ensure that the layer 22 of hard maskmaterial 24 has been etched through its entire thickness. By etchingthrough the layer 22 of hard mask material 24 and into the layer 14, apartial via 32A having sidewalls 44 is formed in the layer 22 of hardmask material 24 and, desirably, into the layer 14. This etching processproduces the sidewalls 44 of the partial via 32A. After the etching ofthe layer 22 of hard mask material 24 has been completed, the layer 40of etch resistant material 42 is removed from the surface of the layer22 of hard mask material 24. The layer 40 of etch resistant material 42can be removed from the surface of the layer 22 in any conventionalmanner known in the art.

[0035] With reference to FIG. 4, once the layer 40 of etch resistantmaterial 42 is removed, the facets 30 in layer 22 of hard mask material24 are formed. The facets 30 are formed by an anisotropic etchingprocess. In this type of etching process, a workpiece is placed on thepowered electrode of a reactive ion etcher, a plasma etcher or othersuitable apparatus capable of accelerating ions toward an object withhigh energy.

[0036] The facet etch used in the present invention has a basis in thephysical nature of the reaction, more specifically, in an ionbombardment. This type of facet etching is most effective when performedin a chamber in which ions can be accelerated to strike the workpiece.Such chambers are known in the art, and include, but are not limited to,reactive ion etchers, desirably magnetically enhanced reactive ionetchers, and high density source etchers.

[0037] In an ion etching or plasma etching process, ions which impinge asurface of a workpiece positioned perpendicularly to the impinging ionshave a minimal effect on etch rate and profile. However, ions strikingthe corners of the workpiece etch at a rate which is about four timesthat of a surface of the workpiece which lays perpendicular to the pathof the impinging ions. This etch creates the gradual slope contacts 46at the corners of the layer 22 of hard mask material 24. The etchingprocess wears away the corners of the layer 22 at approximately 45°angles.

[0038] As shown in detail in FIG. 5, the material removed from thecorners of the layer 22 of hard mask material 24 is redeposited alongthe sidewalls 44 of the partial via 32A to form the deposits 38. Thedeposits 38 further increase the slope of the gradual slope contact 46without widening the via 32. The deposits 38 result from the etchredepositing the removed hard mask material 24 onto the oppositesidewall 26 from the side from which it was removed.

[0039] The facet etch is desirably performed by placing a workpiece in ahigh vacuum reactor on a cathode for which a power source creates aradio frequency (RF) of 13.56 Mhz, while controlling the introduction ofetchant gases. The walls of the reactor are grounded to allow for areturn RF path. This chamber configuration is generally referred to as areactive ion etcher. The RF power source creates a plasma condition inthe chamber, thereby allowing for the creation of charged particles orions. Due to the physics of the RF powered electrode, a direct currentself-bias voltage condition is created at the workpiece location. Thisself-bias condition directs the charged particles or ions toward theworkpiece in a direction perpendicular to the workpiece's surface.

[0040] Typical parameters for facet etching using an Applied Materials5000 Series apparatus or a LAM Research Technologies LAM PCP apparatusare as follows: RF Power: about 300 watts to about 700 watts; Pressure:about 10 mtorr to about 30 mtorr; and Etchant: about 30 sccm to about 70sccm.

[0041] Inert gases, including, but not limited to, argon, helium andxenon are effective etchant gases for performing the facet etch. Theinert gas tends to further enhance the uniformity of the facet etchprocess. An inert gas is used so that the etch of the layer 22 of hardmask material 24 is as close to being a non-chemical etch as possible.In other words, it is desirable that this be as close as possible tobeing a purely mechanical etch. Argon is desired because of its weightand commercial availability but other inert gases may be used. The facetetch can also be performed with any other suitable gas which is inertwith respect to the layer 22 of hard mask material 24 and the layer 14.

[0042] After the facets 30 have been formed in the layer 22 of hard maskmaterial 24, the layer 14 is etched to expose at least a portion of thelayer 18 of conductive material 20, as shown in FIG. 6, and to form asemiconductor device precursor 50. The precursor 50 includes thesubstrate 12 on which the layer 14 has been formed. The layer 18 ofconductive material 20 is formed within the layer 14 and is surroundedby the layer 14. Desirably, the layer 18 of conductive material contactsat least a portion of the substrate 12. As shown in FIG. 6, the layer 22of hard mask material 24 is formed on the layer 14. The layer 22 of hardmask material 24 has the facets 30 formed thereon. The facets 30 and thesidewalls 26, together, define the via 32.

[0043] The precursor 50 is formed by etching the layer 14. The layer 14is etched either isotropically or anisotropically. An isotropic etch isperformed using hydrofluoric acid or any other acid currently used inthe art to wet etch dielectric materials. Desirably, the layer 14 isanisotropically etched using a plasma etch, an ion beam etch or areactive ion etch. More desirably, the layer 14 is plasma etched. Thisetching forms the via 32 which is narrower than the partial via 32Aformed when the layer 22 of hard mask material 24 is etched. This is dueto the fact that the facet etching of the layer 22 of the hard maskmaterial 24, which forms the facets 30, also narrows the via 32 throughthe redeposit of the deposited material 38 along the sidewalls 44 of thepartial via 32A. The narrowing of the via 32 forms the shoulders 36which have the deposited material 38 redeposited thereon.

[0044] After the via 32 has been formed, the metal interconnect 34 canbe formed in the via 32 to complete the semiconductor device 10, asshown in FIG. 1. The metal interconnect 34 is formed to contact thegradual slope contacts 46 and to contact at least a portion of the layer18 of conductive material 20. Desirably, the metal interconnect 34 willbe formed from the same material as the layer 18 of conductive material20.

[0045] Before forming the metal interconnect 34 in the via 32, the via32 may optionally be cleaned of any polymeric material which may havebuilt up in the via 32 during the previous etching processes. To cleanany polymer build up, a mixture of tetrafluoromethane and oxygen gasesis blown at a high temperature into the via 32. This causes any built uppolymeric material to burn making it easier to remove the polymericmaterial with a diluted solution of a mineral acid. However, because theprocess of the present invention removes the etch resistant material 38,which is the primary cause of polymer build up in the via 32, prior toetching of the via 32, such a cleaning step should be unnecessary. If itis necessary, the amount of cleaning required is greatly reduced by theprocess of the present invention as compared to prior art methods.

[0046] After the metal interconnect 34 has been formed in the via 32,the portion of the layer 22 of hard mask material 24 which is notcovered by the metal interconnect 34 may be removed. If the layer 22 ofhard mask material 24 is formed from a conductive material, then theportions of layer 22 which extend beyond the edges of the metalinterconnect 34 must be removed to prevent the layer 22 from acting as aconductive bridge between adjacent interconnects 34. The portions of thelayer 22 of hard mask material 24 which extend beyond the edges of themetal interconnect 34 can be removed by means of either an isotropic oran anisotropic etching process, such as those described above. However,if the layer 22 of hard mask material 24 is not formed from a conductivematerial, it is not necessary to remove the exposed portions of thelayer 22 of hard mask material 24. Further, if the layer 22 of hard maskmaterial 24 is not formed from a conductive material, it may be left inplace to protect the underlying layers.

[0047] A person of skill in the art will appreciate that the aspectratio of the via 32 can be varied by increasing or decreasing thethickness of the layer 14 and/or the layer 22 of hard mask material 24.

[0048] The semiconductor device 10 of the present invention can be anysemiconductor device currently in use in the art. The device 10 can beused as a capacitor, a DRAM, or an SRAM.

[0049] Having described the invention in detail and by reference topreferred embodiments thereof, it will be apparent that modificationsand variations are possible without departing from the scope of theinvention which is defined in the appended claims.

What is claimed is:
 1. A method for forming a semiconductor deviceprecursor comprising the steps of: forming a layer of conductivematerial in a first layer; forming a layer of a hard mask material ontoat least a portion of said first layer; etching said layer of hard maskmaterial to expose a portion of said first layer; forming facets on saidlayer of hard mask material; and forming a via in said first layer, saidvia extending through said first layer to expose at least a portion ofsaid layer of conductive material.
 2. A method for forming asemiconductor device precursor comprising the steps of: forming a layerof conductive material in a first layer; forming a layer of a hard maskmaterial onto at least a portion of said first layer; forming a layer ofetch resistant material on said layer of hard mask material; patterningsaid layer of etch resistant material; etching said layer of hard maskmaterial to expose at least a portion of said first layer; formingfacets on said layer of hard mask material; and forming a via in saidfirst layer, said via extending through said first layer to expose atleast a portion of said layer of conductive material.
 3. A method forforming a semiconductor device precursor comprising the steps of:forming a layer of conductive material in a first layer; forming a layerof a hard mask material onto at least a portion of said first layer;forming a layer of etch resistant material on said hard mask material;patterning said layer of etch resistant material; etching said layer ofhard mask material to expose at least a portion of said first layer andto form opposing sidewalls in at least a portion of said first layer;bombarding said layer of hard mask material with an ion source to formfacets in said layer of hard mask material; depositing a portion of thematerial removed from said layer of hard mask material on oppositesidewalls of said first layer; forming a via in said first layer, saidvia extending through said first layer to expose at least a portion ofsaid layer of conductive material.
 4. A method for forming asemiconductor device comprising the steps of: forming a layer ofconductive material in a first layer; forming a layer of a hard maskmaterial onto at least a portion of said first layer; etching said layerof hard mask material to expose at least a portion of said first layerand to provide said layer of hard mask material with facets; forming avia in said first layer, said via extending through said first layer toexpose at least a portion of said layer of conductive material; andforming a metal interconnect in said via, said metal interconnectcontacting at least a portion of said layer of conductive material.
 5. Asemiconductor device precursor having a gradual slope contact formed bythe method comprising the steps of: forming a layer of conductivematerial in a first layer; forming a layer of a hard mask material ontoat least a portion of said first layer; etching said layer of hard maskmaterial to expose a portion of said first layer; forming gradual slopecontacts on said layer of hard mask material; and forming a via in saidfirst layer, said via extending through said first layer to expose atleast a portion of said layer of conductive material.
 6. A semiconductordevice precursor having a gradual slope contact formed by the methodcomprising the steps of: forming a layer of conductive material in afirst layer; forming a layer of a hard mask material onto at least aportion of said first layer; forming a layer of etch resistant materialon said layer of hard mask material; patterning said layer of etchresistant material; etching said layer of hard mask material to exposeat least a portion of said first layer; forming gradual slope contactson said layer of hard mask material; and forming a via in said firstlayer, said via extending through said first layer to expose at least aportion of said layer of conductive material.
 7. A semiconductor deviceprecursor having a gradual slope contact formed by the method comprisingthe steps of: forming a layer of conductive material in a first layer;forming a layer of a hard mask material onto at least a portion of saidfirst layer; forming a layer of etch resistant material on said hardmask material; patterning said layer of etch resistant material; etchingsaid layer of hard mask material to expose at least a portion of saidfirst layer and to form opposing sidewalls in at least a portion of saidfirst layer; bombarding said hard mask material with an ion source toform gradual slope contacts on said layer of hard mask material;depositing a portion of the material removed from said layer of hardmask material on opposite sidewalls of said first layer; and forming avia in said first layer, said via extending through said first layer toexpose at least a portion of said layer of conductive material.
 8. Asemiconductor device having a gradual slope contact formed by the methodcomprising the steps of: forming a layer of conductive material in afirst layer; forming a layer of a hard mask material onto at least aportion of said first layer; etching said layer of hard mask material toform a sidewall in said first layer and to provide said hard maskmaterial with gradual slope contacts; forming a via in said first layer,said via extending through said first layer to expose at least a portionof said layer of conductive material; and forming a metal interconnectin said via, said metal interconnect contacting at least a portion ofsaid layer of conductive material.
 9. A method for making asemiconductor device having a gradual slope contact comprising the stepsof: forming a layer of dielectric material on a substrate, wherein saiddielectric material is selected from the group consisting of siliconoxide, silicon nitride and polyimide film and wherein said substrate isselected from the group consisting of aluminum, copper andpolycrystalline silicon; forming a layer of conductive material withinsaid layer of dielectric material, said layer of conductive materialbeing surrounded by said layer of dielectric material; depositing alayer of hard mask material on said layer of dielectric material, saidhard mask material being selected from the group consisting of tungsten,tungsten silicide, polycrystalline silicon, titanium, titanium nitride,titanium silicide and titanium-tungsten alloys; forming a photoresistlayer on said layer of hard mask material; exposing said photoresistlayer to form a pattern on said photoresist layer; etching said layer ofhard mask material according to said pattern on said photoresist layerto expose said layer of dielectric material and to form sidewalls insaid exposed portion of said layer of dielectric material; removing saidphotoresist layer; anisotropically etching said layer of hard mask withan inert material to form gradual slope contacts on said layer of hardmask material; depositing said eroded hard mask material onto saidsidewalls of said exposed layer of dielectric material; etching saiddielectric material to expose a portion said layer of conductivematerial; and forming a metal interconnect with said exposed portion ofsaid conductive layer, wherein said metal interconnect is selected fromthe group consisting of aluminum, copper, gold, aluminum-titanium alloysand aluminum-copper alloys.
 10. A semiconductor device precursorcomprising: a substrate; a layer of dielectric material formed on atleast a portion of said substrate; a layer of conductive material formedwithin said layer of dielectric material, said layer of conductivematerial contacting at least a portion of said substrate; and a layer ofhard mask material formed on at least a portion of said layer ofdielectric material, said layer of hard mask material having a pair offacets formed therein by anisotropic etching, said facets and said layerof dielectric material defining a via, said via exposing at least aportion of said layer of conductive material.
 11. A semiconductor devicecomprising: a substrate; a layer of dielectric material formed on atleast a portion of said substrate; a layer of conductive material formedwithin said layer of dielectric material, said layer of conductivematerial contacting at least a portion of said substrate; a layer ofhard mask material formed on at least a portion of said layer ofdielectric material, said layer of hard mask material having facetsformed therein by anisotropic etching, said facets and said layer ofdielectric material defining a via, said via exposing at least a portionof said layer of conductive material; and an interconnect materialformed in said via.